(Hf_(0.25)Zr_(0.25)W_(0.25)Ti_(0.25))B_(2)高熵陶瓷的组织结构与力学性能

Microstructure and Mechanical Properties of(Hf_(0.25)Zr_(0.25)W_(0.25)Ti_(0.25))B_(2) High Entropy Ceramics

为了提高高熵硼化物陶瓷的性能,扩大高熵硼化物陶瓷家族,本文通过硼热/碳热还原法结合SPS制备(Hf_(0.25)Zr_(0.25)W_(0.25)Ti_(0.25))B_(2)高熵硼化物粉末与陶瓷,并对其物相组成、组织形貌和力学性能进行研究。结果表明,经1600℃热处理后(Hf_(0.25)Zr_(0.25)W_(0.25)Ti_(0.25))B_(2)高熵硼化物粉末除了检测出高熵相,还检测到W2B5第二相,粉末粒径为(0.29±0.03)μm;2000℃烧结后W2B5减少,高熵相的衍射峰向高角度偏移,致密度达95.7%,引入WB_(2)后其具有优异的力学性能,硬度(21.3±1.5)GPa,断裂韧性(3.00±0.22)MPa·m^(1/2)。

High entropy boride ceramics have broad application prospects in aerospace,automotive engine and nuclear reactor fields.In order to improve the performance of high entropy boride ceramics and expand the family of high entropy boride ceramics,(Hf_(0.25)Zr_(0.25)W_(0.25)Ti_(0.25))B_(2) high entropy boride ceramic was prepared by boron/carbothermal reduction combined with SPS(Spark Plasma Sintering)in this paper.The phase composition,microstructure and mechanical properties of the powder and ceramic were studied.The results show that after heat treatment at 1600℃,not only the high entropy phase but also W2B5 phase can be detected in(Hf_(0.25)Zr_(0.25)W_(0.25)Ti_(0.25))B_(2) high entropy boride powder(particle size(0.29+0.03)μm).After sintering at 2000℃,the second phase W2B5 decreases,and the diffraction peaks of the high entropy phase shift to a higher angle.The density of ceramic reaches 95.7%.After the introduction of WB_(2),the high entropy boride ceramics exhibit excellent mechanical properties.The hardness is(21.3+1.5)GPa and fracture toughness is(3.00+0.22)MPa·ml/2.